Although sanitary household waste disposal was achieved in China, an efficient source separation system has not been built yet. The Unit Pricing System has been proved effective for household waste sorting by developed countries and regions, while rare developing countries have successfully introduced the system in their local context. The study, taking an interactive perspective of dominant factors of residents’ waste sorting and governments’ intervention, combines theoretical analysis with system simulation to dissect the evolution process of residents’ waste sorting and local governments’ Unit Pricing System policy making, and to provide a Unit Pricing System policy making tool to support policy implementations. The results suggest introducing a Unit Pricing System can significantly push ahead the household waste sorting behaviour for cities with relatively low initial status of environmental awareness, and immediately trigger sorting behaviours for cities with higher initial status of environmental awareness. The study can also benefit other developing countries when imposing waste sorting management instruments.